In general, indoor floors or outdoor floors such as sidewalks or roads are finished with various kinds of materials according to a requirement level of practicality or aesthetics, for example, with tiles, precast pavers or finishing materials. An appropriate construction work is employed according to kinds of tiles, precast pavers or finishing materials.
Thus, in order to finish surface of a floor to be constructed with tiles, precast pavers or finishing materials, flattening of the floor surface should be preceded.
In the case of the conventional art, a worker goes around all over the entire positions on a floor to be constructed with a predetermined tool and instrument by the hand and directly levels the floor even.
Therefore, according to the conventional art, there is a problem that a flattening work of surface of a floor to be constructed cannot be performed rapidly. In addition, since a great number of workers, that is, a great amount of manpower are required in order to flatten a construction surface of a large area, a labor cost rises up greatly. That is, there is a problem that a cost consumed for a flattening process of the construction surface of the floor to be constructed rises up.